In electronic or automatic toll collection applications, it is desirable to correctly identify a vehicle traveling on the roadway and to determine the path of the vehicle on the toll roadway for billing purposes. Furthermore, vehicles are identified by vehicle transponders which are read by automatic vehicle identification (AVI) readers located along a roadway or at toll collection stations. Automatic toll collection systems also identify vehicles by reading license plate numbers. License plate reading systems include cameras which capture license plate images that are subsequently read by an automatic optical character recognition (OCR) processors and manually read by human operators to provide license plate numbers. Both the transponder system and license plate reading system are subject to errors which degrade performance and reduce revenues of the toll collection system.
In an open ticket toll collection system (also referred to as an open-road, no lane barrier system), toll gateways are placed along the mainline roadways as opposed to a closed ticket system which includes toll gateways at the roadway entry and exit points. Open ticket systems are desirable due to reduced infrastructure requirements, but it is difficult to determine when vehicles actually enter and exit the roadway since there is no positive confirmation of these events. As a result, it is not possible to bill vehicles on a trip basis or develop a traffic model of how vehicles are actually using the roadways.
One conventional solution has been to bill a set amount for each toll gateway crossed. While simple, this approach cannot support trip based billing which is desirable for many reasons including: (1) support for minimum and/or maximum trip charges; (2) simplified statements; (3) accurate traffic models; and (4) reducing losses from non-functional tolling equipment.
Conventional systems use a combination of electronic and manual toll collection and the system operators have chosen to treat the electronic portion merely as a convenience, (e.g. ‘fast lanes” or “express lanes” to allow drivers to bypass manual toll booths). These conventional systems automate existing manual systems and keep the same rules that apply to the manual system rather than attempt true trip based billing.
In complicated automatic toll collection systems, there is a high probability that a system data error will produce incorrect billing information. The automatic toll collection system is also subject to toll evasion by several means including stolen or improperly used transponders and license plates. In typical automatic toll systems, incorrect identification of a vehicle or non-identification of a vehicle is costly. In conventional systems the error rate ranges from two percent to ten percent. An error in a license plate reading results in lost revenue, increased customer support expenses and customer dissatisfaction when a customer is incorrectly billed. When a vehicle identification cannot be made either by a transponder or license plate reading, the toll revenue is not collected.
It would, therefore, be desirable to provide a reliable trip determination system in an open ticket toll collection system and combined open ticket and closed ticket system to support trip based billing. It would be further desirable to provide a method to determine system malfunctions and to identify possible toll evaders.